Fin mast antenna



June 20, 1944. vo 2,351,723

FIN MAST ANTENNA Filed May 22, 1943 Patented June 20, 1944 FIN MASTANTENNA Arthur G. Vogel, Chicago, Ill., assignor to Rempe Company,Chicago, 111., a. corporation of Illinois Application May 22, 1943,Serial No. 487,996

1 Claim.

My invention relates to mast antennas for radio reception. Its object isto improve radio reception, especially with the type of mast antennawhich is directionally adjustable. The improvement in reception isachieved by my invention without increasing the length of the mastantenna and without increasing the transverse dimensions thereof to anextent appreciably to complicate packaging it, or to interfere with itsjuxtaposing a wall which it may parallel.

Also, by my invention I may laterally extend the surface as amultiplicity of surfaces in condenser-like relationship and at normalsto the axis of the mast, which extended surface is rather compactlyarranged about the mast and rigidly fixed thereon and supported thereby.

My invention also concerns an improved insulated mounting and adjustablebracketing of the antenna mast.

The foregoing, together with further objects, features, and advantagesof my invention, are set forth in the following description of aspecific embodiment thereof as illustrated in the accompanying drawingwherein:

Fig. 1 is a perspective view of the fin mast antenna of my inventionmounted on a window frame; and

Fig. 2 is a longitudinal vertical section thereof.

My fin mast antenna II), as a whole, is shown as mounted on the exteriorframe I I of a window and preferably swung and inclined somewhatupwardly of a direction toward the transmitting station from whichreception is most sought. The backbone or mast proper of my antenna is atube I2 of high conductivity metal preferably of uniform externaldiameter. Upon this tube are rigidly mounted, at spaced intervals, amultiplicity of fins I3. While these fins may be discs, I prefer thatthey be squares of thin sheet stock of a high conductivity metal such ascopper.

Each fin I3 has a central hole l4 whereby the fins can be slipped uponthe tube. The central hole I4 of each fin may be margined by a narrowflange I5 making surface contact with the periphery of the tube.

The fins are made fast upon the tube in any well-known manner such as byinternal expansion of the tube, by crimping the flange I 5 upon thetube, by making the hold I I such a tight fit that the fins areadequately fixed by friction, by welding, or by a metal bath.

Whatever be the specific technique employed for fixing the fins, theyare made sufiiciently fast to preserve them, under ordinary treatment,at normals to the axis of the mast whereby each fin is maintainedsubstantially parallel with its neighboring fins.

I have found that, balancing cost and weight against performance, it ismost desirable that the inter-fin spacing be in the order of about halfthe fin width, and that the fin width be several times the tubediameter.

The upper end of the tube may be closed by a pointed plug I6 preferablyof metal.

The lower end of the tube I2 is fitted into the socket Ila of a piece ofinsulation I1, and is fixed therein as by cementing. The piece ofinsulation I 7 also preferably embodies a convex dished shield no, themargins of which are undercut to shed water.

The bottom end of the piece of insulation IT is conformed as a threadedstud lie. The socket I7a preferably extends, as shown, well down intothe interior of the threaded stud Ilc, whereby the metal tube I2 servesto reinforce the insulation piece at the neck of the stud I'Ic where thepiece of insulation would otherwise be most likely to break.

The stud IIc threads into the socket I8 of the ball member I9 of a mastmounting which also includes a complementary or socket member 20 fixedto the window frame or other supporting surface as by wood screws 2|.The ball and socket members I9 and 20, which may be of metal, permit auniversal direction adjustment of the mast antenna, which adjustment maybe fixed by socket clamping thumb screws 22.

The lead-in conductor 23 may conveniently be connected to the base ofthe tubes or, as here shown, to the lowermost fin. My fin mast antennais disposed with its axis in a more or less vertical position andconsequently the several fins are in more or less horizontal positionand thereby in turn more or less parallel with the ground, tendingtoward increasing the condenser capacity of the antenna in its radioreception.

By the compactly arranged surface extension at normals to the axis of myantenna its condenser capacity is greatly increased for the improvementof radio reception, without increasing its over-all length and. withoutsubstantially increasing the over-all transverse dimensions of theantenna beyond those of the usual shield and mounting.

I claim:

A mast antenna for radio reception comprising a supporting means adaptedto be secured to a building or other supporting structure including apair of metallic members one of which is adapton said plates formounting said plates in spaced relation directly on said mast comprisingan aperture in each plate having a margin defined by a flange, saidflange making low impedance surface contact with said mast and means forfixedly mounting said flange on said mast whereby said tubular mastforms the sole support for said plates, said mast and platesconstituting the effective antenna, and a lead-in conductor con- 10nected to said effective antenna.

ARTHUR G. VOGEL.

